Arctic Sea Ice Shrinks to Its 2026 Minimum

This item is an update to the Arctic sea ice feature in the World of Change series, which uses satellite imagery to track long-term change on Earth's surface. A layer of frozen seawater caps the Arctic Ocean; it grows through the long polar winter, usually peaking in March, then melts through summer to its annual low in September. That cycle is a natural fluctuation that has persisted for millennia, but satellite records show the ice now covers less of the Arctic Ocean at both its annual maximum and minimum than it did a few decades ago.

Arctic sea ice in 2026 reached its annual minimum extent on September 12, covering an estimated 4.6 million square kilometers (1.78 million square miles), according to NASA and the National Snow and Ice Data Center (NSIDC). That ties 2008, 2010, and 2025 for the 10th-lowest minimum in the satellite record. The accompanying maps pair each September since 1990, around the ice's annual minimum, with the following March, near its annual maximum, through March 2026.

Scientists have used satellites to observe the annual growth and retreat of Arctic sea ice continuously since late 1978. Sea ice extent has declined overall during that period, and the downward trend steepened in the 2000s, setting off a run of record and near-record lows. Each of the past 20 summers, from 2007 through 2026, ranks among the 20 lowest minimum extents in the satellite record, with the lowest occurring in September 2012. More recently, September sea ice extent has been relatively steady; weather can make a big difference from one summer to the next, and over the past decade increased cloud cover has prevented sunlight from accelerating the melt, according to NASA scientists. Despite this recent plateau, the summer minimum remains well below the long-term average.

Across the Arctic, the ice that remains is younger and thinner. Observations show a decline in multiyear ice—ice that survives at least one melt season—leaving an Arctic dominated by thinner first-year ice. Winter ice is also shrinking: the March 2026 maximum statistically tied the 2025 maximum for the lowest in the satellite record.

Cycles of natural variability such as the Arctic Oscillation are known to play a role in Arctic sea ice extent, but the decline observed throughout the satellite record cannot be explained by natural variability alone. Natural variability and rising global temperatures have worked together to melt greater amounts of Arctic sea ice. Scientists have projected that an essentially ice-free Arctic could occur at least once before the middle of the 21st century.

To determine sea ice extent, scientists rely on satellites with passive microwave sensors that measure the microwave energy Earth naturally emits. Sea ice emits more of this energy than open water, so it stands out in microwave images. Because microwaves pass through clouds, the satellites can observe sea ice regularly regardless of weather; the record began in late 1978.